Self-regulating hydraulic elevator



(No Model.) 2 Sheets-Sheet 1.

W. E. DIIGKEBSODI. SELF REGULATING HYDRAULIC ELEVATOR. No. 404,726.Patented June 4. 1889..

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w. E. NIOKERSON. QELF REGULATING HYDRAULIC ELEVATOR.

No. 404,726. Patented June 4, 1889.

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- UNITED STATES PATENT OFFICE.

IVILLIAM E. NICKERSON, OF CAMBRIDGE, MASSACHUSETTS.

SELF-REGULATING HYDRAULIC ELEVATOR.

SPECIFICATION forming part of Letters Patent No. 404,726, dated June 4,1889.

Application filed March 25, 1889- Serial No. 30 },700- (No model.)

To aZZ- whomiit may concern:

Be it known that LI/VILLIAM EMERY NICK- ERSON, of Cambridge, in thecounty of Middlesex and State of Massachusetts, have invented certainnew and useful Improvements in Self- Regulating Hydraulic Elevators, ofwhich the following, taken in connection with the accompanying drawings,is-a specification.

My invention is embodied in a device connected to the carriage-movingmechanism of a hydraulic elevator; and it consists of a piston adaptedto move at a velocity bearing a constant ratio to the velocity of theelevatorcarriage, said piston in its movements causing a flow of wateror some other fluid through a passage so proportioned that when thecarriage is moving at or within its normal veloc-' ity then there willnot be any tendency to either too great a pressure under the piston or avacuum, and in connecting to the above cylinder a second cylinder havingwithin it a piston connected to a valvewhich regulates the flow of fluidinto or out of the hoisting-cylinder and thus regulates the velocity ofthe main piston and through it the velocity of the carriage.

In describing my invention I make use of the accompanying drawings, inwhich Figure 1 is an elevation of one mode of-applying my regulatingdevice to an elevator. Fig. 2 is a view, partly in elevation and partlyin vertical section, showing the leading features. Fig. 3 is a planshowing most of the parts. Fig. 4 is a View in elevation and section ofa modification. 1

In Fig. 1 the carriage O is represented as part way up and suspended bythe hoistingrope A which passes over the pulley A down to and under thepulley A attached to the piston-rod A, and thence up to the point a,where it is firmly secured. The piston-rod A is connected to the mainhoisting-piston (not shown) within the hoisting-cylin der A.

As a convenient means of connecting my regulating device to the movingmechanism to the form of elevator shown, I attach an aim A to thepiston-rod A, and to this arm A, I attach a rope B, said rope R passingaround the drum R a suflicient number of times and preferably fastenedto it to secure a rotation of the pulley with any movement of the rope.At the lower end of the rope R, I

have a weight T, which serves as a retractor. A train of gears R R Rconnect the shaft R of the pulley R to the rack R formed on thepiston-rod of the piston R The piston R moves in a cylinder R andthrough the means above described is moved by the action of the water inthe hoisting-cylinder Athat is, it moves as the elevator-carriage movesand with a velocity that always has a fixed ratio to the velocity of theelevator-carriage. The movement of the piston R in the cylinder R ofnecessity causes a flow of thefluid in the cylinder R through the pipe Rand as this pipe R has a regulating-valve at R by which the flow offluid can be regulated or restricted, it is evident that pressure uponthe fluid under the'piston B may be made more or less for a certainvelocity of the piston It by setting the valve It It Willbe observedthat as the piston R descends the pressure is increased and is positivein relation to the ordinary atmospheric pressure,

and as the piston R ascends the pressure is negative as to theatmospheric pressure. I I take advantage of this varying pressure of thefluid in the lower part of the cylinder R for the purpose of moving theregulatingvalve E of the main cylinder A.

. My device for utilizing the varying pressure of the fluid in thecylinder R due to the velocity of mot-ion of the carriage as transmittedto the piston R for the purpose ofregulating the velocity of movement ofthe hoisting-piston, and consequently that of the elevator-carriage, Iwill now describe.

P, Figs. 1 and 2, represents a pipe leading from the cylinder R to thevalve-operating cylinder D This cylinder D has a piston D (see Fig. 2,)which is connected by a rack D to the rack-pinion D on the shaft d ofthe regulating-valve E. The valve E is placed in the pipe D and is notintended to entirely prevent the passage of water through it, but simplyto check it to the required degree for insuring the normal velocity ofthe elevator-carriage.

The shaft (Z of the valve E has upon it a pulley E, about which a cord EE passes. The cord E E is so attached to the pulley that it cannot slip,and if the pulley E is turned in either direction by the movement of thepiston-rod rack D then one of the weights WV WV will be lifted from itsrestingplace Thus the weights IV \V, when in the normal position-thatis, resting upon the shelf VW-will hold the pulley E in such a positionthat the valve E will be wide open and admit of the free passage ofwater through the pipe I) in either direction.

\Vater is let on to or cut oil from the cylinder A by means of a valvein the cylinder B Fig. 1. This valve is operated by the hand-rope B,which passes through the elevator-carriage C, about the sheaves 13, Band B to the pulley B, which acts through the pinion B and rack-pistonrod B, the hand-rope B being operated by the attendant in the usualmanner.

In Fig. 4 I have shown a slight modification of my device. Thismodification consists in forming the cylinder R long enough to includeaspace for the piston D of the cylinder D of Fig. 2 to work in. In otherwords, the cylinders R and D of Fig. 2 are inserted in a single longcylinder, as shown in Fig. 4, all of the other parts being essentiallythe same in construction and operation.

The operation of my device is as follows: Suppose, for instance, thatthe elevator-carriage is going up. This action of the carriage willcause the piston R (see Fig. 2) to descend. Now, if the descent is toorapid, then the fluid in the cylinder R cannot flow rapidly enoughthrough the pipe or passage R and consequently will generate suflieientpressure under the piston R to send the surplus of fluid through thepipe P into the lower part of the cylinder D and force the piston Dupward, overcoming the tendency of the weight IV to hold the valveE wideopen, and causing (through the rack D and pinion D the valve E to partlyclose and check the flow of water through the pipe D, and thus reducethe speed of the elevator-carriage. If the elevator were going down,then the piston R would be going up, and it moving too rapidly the fluidfrom the upper part of the cylinder B would not flow fast enough throughthe pipe R to supply the tendency to a vacuum in the lower part of thecylinder R hence fluidwould be drawn from the under side of the piston Din the cylinder This would draw the piston D down, and, acting throughthe rack and pinion D D would partly close the valve E in opposition tothe weight \V, and check the flow of water in the pipe 'D, andconsequently the speed of the ele vator-carriage, as before. As hasalready been explained, any movement of the valve E from its wide-openor normal posit-i011 will cause a movement of the pulleyE andconsequently the lifting of one of the weights IV \V, and sustaining itso long as the force due to too great a speed of the elevater-earriageis exerted on the piston I)"; but as soon as the force is withdrawn, asit will be by the lessened speed of the elevator-carriage, then theweight IV or WV, that is held up,will descend to its resting place andrestore the valve E to its normal position.

111 the device shown for transmitting the motion of the prime mover tothe regulating apparatus I have shown a gear-and-rack device forreducing the amount of motion of the main piston so as to cause thepressurcpiston R to be confined in its length of stroke to a shortcylinder; butin practice the piston R may be so connected to the pistonof the prime-mover that it may have a length of stroke equal to or evenexceeding the length of stroke of the piston of the prime mover.

It is evident that the velocity of movement sufficient to cause thethrottle-valve E to shut off is dependent on the one hand on the amountof restriction imposed on the flow of liquid by the valve R and on theother hand on the size of the weights IV \V, so that the limit of speedof the elevator is set by varyin g either the opening of the valve R orthe size of the weights W XV, or both.

I claiin 1. In a hydraulic elevator, the combination of the mainhoisting-piston and its cylinder, and a port for inlet and outlet havinga throttle-valve held normally open by a re tractor device, with apiston located in a fluid-cylinder and adapted to close saidthrottle-valve (when the hoist-ing mechanism of the elevator attainsundue speed) by impulse generated by the motion of a secondary pistonadapted to move with a fixed ratio to the hoisting mechanism, saidsecondary piston being located in a secondary cylinder having arestricted passage from one side of its piston to the other, and a fluidconnection with the cylinder containing the Valve-moving piston,substantially as described, and for the purpose set forth.

2. In a hydraulic elevator, the combination of the main cylinder A andits piston and piston-rod, port D, for inlet and outlet, having athrottle-valve E, and valve-retractor device consisting of the pulley E,rope E" E, and weights \V V, with the piston-rack D piston D, cylinder Dpipe P, cylinder R havin g a restriction-pipe R ,and piston RQad aptedto move in a fixed ratio to the movement of the elevator-carriage,substantially as and for \VILLIAM E. NICKERSON.

\Vitnesses:

FRANK G. PARKER, MATTHEW M. BLUNT.

